The present invention relates to an image scanner provided with a power saving mode, for example, a simplex image scanner used as a peripheral device of a personal computer and a printer provided with an image scanner.
An image scanner which has a body provided with an original table having a surface such as a glass table for putting an original and which scans images of the original put on the surface of the original table is already known. This type of image scanner is provided with an original cover which can be opened and closed for pressing the original table, a fluorescent lamp as a light source and a charge-coupled device (CCD) that senses reflected light on the original of a beam emitted from the fluorescent lamp and converts it to an electric signal for example. Further, this type of image scanners have a power saving mode for suppressing the power consumption of the whole device (refer to a patent document 1). These image scanners stop the supply of power to the light source in case the power saving mode is turned on and start the supply of power to the light source again in case the power saving mode is released (see FIGS. 1A and 1B of the patent document 1).
As described above, some image scanners having the power saving mode release the power saving mode when a user presses a predetermined button (in case the image scanner is a copying machine, the button is equivalent to a copying execution button) in the power saving mode. However, in order to reduce total time for reading more, one of conventional type image scanners monitor an output signal value from CCD, senses that the original cover is opened in case the output signal value increases and starts the supply of power to the light source (refer to a paragraph 40 of the patent document 1). Besides, the conventional type image scanners stop the supply of power to the light source when fixed time elapses after reading operation is finished (refer to paragraphs 66 and 67 of the patent document 1).
Patent Document 1
JP-A-6-309449
According to the conventional type image scanner, it is detected that the original cover is lifted, in other words, a sign that the image scanner may be used by a user (hereinafter called a sign of use by a user) is detected. However, the sign of use by the user other than the original cover is lifted may be considered. If such another sign of use by a user can be detected and the power saving mode can be released, the total reading time of the image scanner can be more reduced.